In food establishments such as fast food outlets, there are conventionally provided beverage dispensing machines capable of dispensing a large number of beverages of different brands and flavors. These beverages are usually poured into disposable paper cups having the same appearance and bearing no markings to identify the cup's contents.
When a beverage order includes a number of different brands and flavors, it is extremely difficult to determine the contents of each cup by visual inspection. Identification is further complicated by the placement of lids over the cups to prevent spillage.
As a consequence of this problem, mixups occur and persons get the wrong drink and do not discover the error until tasting the beverage.
One way in which this confusion can be resolved is by using paper cups of different colors or having different designs or markings thereon. However, this requires a large inventory of cups, and the cups must be carefully selected by the person filling the order in order to avoid the error of filling the selected cup with the incorrect beverage.